Rock-drill.



T. E. ADAMS.

ROOK DRILL. APPLIUATION FILED JULY 23,'190'1.r 91 3,932. Patent-ea Mar. 2, 1909.

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ISTNESES 'I'. E. ADAMS.

BOGK DRILL.

PrLIoATIon FILED JULY 23,1907.

Patented Mar. 2, 1909.

4 SHEETS-SHEET 2.

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T. E. ADAMS.

BOGK'DBILL.

APPLICATION FILED JULY 23, 1907 4 SHEETS-SHEET 3.

INVENTOR' VPatented Mar. 2, 1909.

` `I.|I llllllllullllllllrl u WTNESSES fd/V T. E. ADAMS.

ROCK DRILL.

ArrLIoATIoN FILED JULY 23,1907.

91 3,932'. Patented Mar. 2, 1909.

4 SHEETS-SHEET 4.

UNITED STATES IrrENr EEcE.

THOMAS EDGAR ADAMS, OF CLEVELAND, OHIO.

ROCK-DRILL.

To all whom it may concern:

Be it known that I, THOMAS E. ADAMS, a resident of Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Rock- Drills and 1 do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in rock drills and more particularly to such in which the forward thrust of the drill rod is effected by spring power and in which the drill rod is turned during its return or rearward movement.

lt has been found that during the operation of a rock drill in which the forward driving of the drill rod is effected by spring power, as heretofore constructed, the drill rod and its tool are liable to rebound when the latter strikes the rock, so that the propelling springs may be compressed to an abnormal extent preparatory for the next forward thrust ofthe drill rod and result in propelling the drill rod with varying degrees of force. This is liable to happen in a rock drill in which the propelling` springs are compressed during the rearward or return stroke of the drill rod, and in which the latter is withdrawn by means of a clutch device which is tripped to release the said drill rod at the end of its return or rearward stroke. Again, with rock drill operating mechanism of the character to which allusion is above made, the propelling springs are subjected to more or less torsional or twisting strain during the rotative motion of the drill rod while the latter is being withdrawn, and the springs will thereforev tend to rotate the drill rod backward when released to force said drill rod forward, thus causing a loss in the extent of rotative motion of the bit or drill tool. Such operation is liable to occur more particularly in a rod drill in which the propelling spring is arranged axially with respect to the drill rod.

One object of my invention is to improve the construction of a rock drill in which the drill rod is propelled by spring power, and to provide means whereby the degree of force applied to the drill rod will be uniform with successive forward thrusts of the same.

A further object is to so construct a rock drill of the character described that the com- Specification of Letters Patent.

Application filed July 23, 1907.

Patented March 2, 1909.

Serial No. 385,111.

operating mechanism by which the drill rod is withdrawn.

A further object is to provide a structure in which the propelling springs will be el'ectually housed and protected.

A further object is to provide improved means for withdrawing` and releasing the drill rod.

A further object is to provide simple and e'llieient means for preventing torsion of the propelling springs and to overcome any effect which torsion of said springs might tend to have upon the drill rod.

A further object is to improve a rock drill structure in other respects hereinafter described.

Vith these objects in view, the invention consists in certain novel features of construction and combination and arrangements of parts as hereinafter set forth and pointed out in the claims.

1n the accompanying drawings, Figure 1 is a longitudinal sectional view of a rock drill embodying my improvements, the motor being shown in elevation; Fig. 2 is an enlarged sectional view, partly broken away, taken at right angles te Fig. 1, through the motor and a portion of the drill operating mechanism; Fig. 3 is a section on the line a-a of Fig. 1; Fig. 4 is an enlarged section on the line b--b of Fig. 1 Fig. 5 is an enlarged section on the line c-c of Fig. 1 Fig. 6 is an enlarged section on the line d--d of Fig. 2 with the crank at its lowest position; Fig. 7 is an enlarged detail view of the trip lever; Fig. 8 is an enlarged detail view of the yoke which connects the shoes or jaws of the clutch with the trip lever g Fig. 9 illustrates the ring 20 and bushing 23 in section and enlarged.

1 represents the guide shell, upon which the drill barrel 2 is mounted to move longitudinally. To e'll'ect such movement for feeding the drill toward or away from the rock, a screw 3 is provided, said screw having a swivel mounting in the 'fixed framework of the machine and passing through y screwed through the ring 20.

form and receives a reciprocating drill rod 9. The rear end of the drill rod is provided with an enlarged hollow head 10 movable as a piston within the barrel 2, and the forward end of said drill rod projects beyond the forward end of the drill barrel and provided with a socket for the accommodation of a drill bit or tool 11. A bushing 12, having an elongated slot 12a, fits within the socket in the forward end of the drill rod and at its rear end, rests against the head of a die 13. This die projects rearwardly and its pointed rear end 14 enters the hollow interior of the tubular portion 15 of the drill rod, for a purpose hereinafter explained.

The rear end of the bit 11 rests against the head of die 13 and the wall of the socketed portion of the drill rod is made with an elongated slot in alinement with the slot 12a of bushing 12, for the accommodation of a wedge-shaped key 16, the inner edge of which engages the bit 11. The key 16 is forced tightly against the bit 11 to secure the latter in its seat in the end of the drill rod, by means of a collar 17 having an interior, longitudinal groove for the accommodation of said key. The collar 17 is mounted so that it can slide on the drill rod, its rearward movement thereon, being limited by a shoulder 1S. The key 16, collar 17 and the socketed end of the drill rod thus constitute a chuck for securing the bit in place, an d the latter can be readily removed by sliding the collar until it engages the shoulder 18, which movement of the collar will permit the key to be sufliciently Withdrawn to release the bit. The collar 17 also constitutes an abutment for the drill rod against a series of bufling springs 19 carried by the drill barrel. The springs 19 are seated in sockets in a ring 20 and project forwardly beyond said ring so that they may be engaged by the chuck collar 17 when the drill rod makes its rearward or return throw. The bottoms of the spring sockets are undercut as shown at 21 to receive the end convolutions of the coils to prevent the escape of the latter.

The ring 2O is threaded externally and screws into the forward' end of the drill barrel, said ring having an annular, notched flange 22 which rests against the forward end of the barrel. The inner face of the ring 2() is made somewhat conical and screw threaded'. A bushing 23 for the drill rod, is made with a conical, threaded exterior and is The bushing 23 is provided in its forward end with a se- Y ries of notches 25 for the accommodation of a the forward end of the piston head 10 of the drill rod and thus cushion the forward throw of the latter. il shaft 30 is mounted in the rear end of the drill barrel 2 and provided between its ends with a crank arm 31.

Diametrically opposite walls in the rear portion of the drill barrel or body 2 are provided with spiral grooves or guide-ways 34 in which the end of a cross-head 33 on a drawbar 32 are adapted to move. The cross head S8 is made with an elongated opening 35 which receives a bearing box 36 mounted suaiciently loose on the crank arm 31 of shaft 30 to permit the cross head of the draw bar to move in the spiral grooves 34 when the crank shaft is operated. 1n this manner, an oscillatory as well as a reciprocating motion will be given to the draw bar, and both of these motions will be imparted to the drill rod during the rearward movement of the draw bar, provision being made, (as presently described) to couple the draw bar with the drill rod only during the rearward stroke of said draw bar. rlie forward end of the draw bar 32 is contracted to form an annular shoulder 37 and beyond said shoulder, the forward portion of the draw bar is threaded for the reception of a wedge-block 38 having a series of beveled faces 39 for a purpose hereinafter explained. rlhe wedge-block 3S is provided with elongated tubular extension 40 the forward end of which enters andhas sliding movement within the tubular portion of the drill rod. rlhe tube 40 and the tubular portion of the drill rod serve to house the propelling springs l1 for the drill rod. 1 prefer to employ two pairs of these springs, the springs of each pair located one within the other, and the pairs of springs disposed, respectively, in the tube l0 and the tubular portion of the drill rod and separated by a spacer 421 rlhus it will be seen that the rear ends of the propelling springs of one pair, bear against the forward end of the draw bar and wedge block, while the forward ends of the other pair of propelling springs bear against a seat i3 mounted to turn on the pointed inner end of the die 13. By thus mounting the propelling springs, torsion thereof, when the drill rod is turned as hereinafter described, will be reduced to a minimum.

Means are provided for withdrawing the be subjected to the propelling action of the springs 41, and in order that these springs may exert a propelling power, they must hrst be compressed so as to store such power. It has been found however, as previously stated, that if the springs are compressed simultaneously with the withdrawing of the drill rod, the latter is liable to rebound when the bit strikes the rock and prevent the proper operation of the machine to effect uniform strokes. l therefore propose to compress the propelling springs during the forward stroke of the withdrawing means, so that when a bit strikes the rock, the effect of the rebound will be counter-acted by the forward compressing of the springs for the next stroke.

The means which accomplish the results abpve alluded to, will now be described in detai An annular series of clutch shoes 43a surround the wedge-block 38 and each has a beveled inner face disposed against one of the beveled outer faces 39 of the wedge block. The clutch shoes 43l are provided with grooved outer faces and enter the hollow head or piston 10 which constitutes the rear end of the drill rod. Each clutch shoe is made with a socket, in each of which a spring 44 is located. The rear ends of these springs bear against a ring 45 encircling the contracted forward portion of the draw bar 32 and bearing against the annular shoulder 87,-said springs tending to normally press the shoes 43a forwardly on the beveled wedge block 38 and cause them to come into clutching contact with the interior of the piston head 10. It is apparent that if the piston head be thus clutched when the clutch devices are in the forward portion of said piston head, the rearward movement of the draw bar will cause the withdrawal of the drill rod.

Each clutch shoe is provided with a rearwardly projecting hook shaped arm 46 which engages a yoke or forked member 47 mounted to move longitudinally on the draw bar. The draw bar 32 is recessed in proximity to its cross head 33 and provided with a rib 48 which constitutes the fulcrum of a trip lever 49, the latter being provided at its upper end with a perforated boss 50, in the under face of which, a groove 5l is made for the accommodation of the rib 48 on which the trip lever is mounted. The ends of the boss 50 are countersunk and receive the rear ends of the respective arms of the yoke 47, these parts being pivotally connected together by means of a trip pin 52. Below its bearing upon the rib 48 the trip lever is provided with a shoulder 53 which enters a re cess 54 in the draw bar. The trip lever is so disposed that when it is turned in one direction, its depending portion 55 will be made tov project into the e ongated opening 35 in the cross head 34 and in the path of the bearing box 36 on the crank arm 31 of the shaft 3l). Now, when the parts become so disposed that the crank arm 31 and the bearing box 36 thereon are out of line with the trip lever, the clutch springs will tend to force the clutch shoes forwardly and this movement of the clutch shoes will be transmitted through the medium of the yoke 47 to the trip lever and cause the latter to be moved so that it willproject into the opening 35 of cross head 33 'in the path of movement of the crank arm 31 and bearing box 36 thereon. When the parts are in such positions, the draw bar and drill rod will be coupled together.

When the draw bar is moved forwardly by the crank shaft, the bearing box 36 on the crank arm 31 will move in such direction through the opening 35 of cross head 34 as to force the depending portion 55 of the trip lever from the position just described to the position shown in Fig. 1 and thus cause the reverse operation of the clutch device to that above described, and the release of the clutch shoes from the head or piston 10.

As the forward movement of the draw bar continues, the clutch will move freely in the head or piston 10. During such movement of the parts, the bit at the end of the drill rod will be resting against the rock, (assuming that the machiney is preparing to make its initial stroke), and the propelling springs 41 will become compressed. Villien the draw bar shall have completed its forward throw, the bearing box on the crank arm of the shaft 80 will move out of line with the trip lever, and thus permit the depending portion 55 of the trip lever 49 to be moved into the opening 35 in the path of the crank arm 31 and bearing box 3G by the operating of the clutch springs, the same action of the clutch springs serving to cause the clutch shoes to engage the inner face of the hollow piston 10 near the forward end of the latter. T he draw bar and drill rod are now secured to* gether through the medium of the clutch, and during the remaining half revolution of the crank shaft, its crank arm will move in that portion of the cross head 33 farthest removed. from the trip lever, so that as the draw bar is moved rearwardly by the crank shaft, the trip devices will not be disturbed, and the clutch therefore remains in locked engagement with the head 10 of the drill rod and withdraws the latter, with `the propel ling springs compressed therein. As the crank arm of the shaft 30 approaches the completion of its revolution, the bearing box 36 thereon, will engage the trip lever and force it to the position shown in Fig.l 1 thus withdrawing the vclutch shoes as previously explained, and releasing the drill rod, which latter will now be forced forwardly by the propelling springs 4l to strike a blow. Should the drill rod tend to rebound after the bit strikes the rock, the effect of such rebound will be neutralized or at least checked and in some cases entirely prevented by the propelling springs, the compression of which for the next stroke, will promptly commence as the draw bar and clutch nieves forwardly after the drill rod has been released. Thus when the clutch reaches the forward end of its movement preparatory to the second forward thrust of the drill rod, the bit will be resting against the rock as before, and hence the clutch will always engage the ing the rearward throw of these parts'.

piston head 10 at the same place, and the strokes of the drill rod will be uniform.

1t has been found that if the crank shaft be turned by hand so as to produce a slow reoiprocation of the draw bar, the blow struck by the drill will not be as hard as when the draw bar is caused to reciprocate rapidly by the operation of the motor. The reason of this is that when the machine is running at the proper speed so as to reciprocate the draw bar rapidly, and the clutch releases the drill rod at the end of each return stroke, the speed is such that the blow is caused not only by the expansion of the propelling` spring itself, but the crank blowis largely added. in other words, when the crank shaft is operated rapidly by the motor, the crank and draw bar will follow up the rear of the propelling spring, resulting in a remarkably hard cutting blow of the tool, whereas, when the crank shaft and draw bar are operated slowly by hand, the spring will have had time to reach the end of its expansion before the draw bar, by its forward movement, again compresses the spring.

The drill will preferably be so set that when the drill rod is withdrawing, the chuck collar will strike the buffing springs with but light pressure, and the operator will know when the drill is working properly, by watching the extent to which the bufling springs are being compressed. wWhatever power is stored by compression of the buffing springs will operate to augment the propelling springs 41 in effecting the forward thrust of the drill rod. As hereinbefore stated, the draw bar is oscillated during its reciprocating movements, but this oscillatory motion is positively transmitted to the drill rod only while the latter is clutched to the drawbar dur- As one of the propelling springs 41 bears against the draw bar and the other end against the drill rod, and as the draw bar has a turning as well as a longitudinal movement independently of the drill rod, when said draw baris making its forward movement, there will be a tendency to subject the propelling springs to a torsional strain which. (if not relieved) would tend to turn the drill rod backwardly and a loss in the rotative movement of the drill rod and its bit would be the result. To avoid such torsional strain on the springs and the evil effects of the same, is the purpose of the rotatable seat 43 for the propelling springs.

It is desirable vthat the turning of the drill bit should not be greater nor less in degree than the turning of the draw bar. In other words the drill bit should be turned a uniform distance during all return strokes of the same. 1n order to insure such action in all cases, I employ the devices now to be described:

The piston head 1() is made with an annular series of teeth 56 and the wall of the drill barrel 2 is provided with an elongated slot 57 y through which a plate 58 projects, said plate having a series of grooves forming teeth 59 which bear against the teeth 56 on the iston head of the drill rod. The grooved plate is mounted in a frame comprising blocks 60 located in the elongated slot 57 and a plate 61 riveted at its ends to such blocks and secured in place by screws 61a. The grooved plate is limited in its movement toward the piston 10 by means of shoulders 62 on the plate engaging shoulders 63 on the blocks 60. A spring 64 is disposed between the plate 61 and the grooved plate 58 and serves to press the latter against the toothed peripheral portion of the piston 10. The pressure of the toothed plate 58 against the toothed periphery of the piston 10 will cause such resistance to the rotation of the latter as to prevent its momentum from causing it to turn further than the oscillating movement of the draw bar will turn it. In other words, the springpressed plate acts as a brake or resistance device to prevent the drill rodfrombeing turned too far by momentum. Thus it will be seen that the grooved plate, cooperating with the toothedportion of the piston 10, serves to assist in insuring the measured turning of the latter and the drill rod and prevent the same from turning farther than the draw bar is turned, the turning or oscillation of the latter being effected by the movement of the drawbar 32 in the partially-spiral guide-ways 34. The uniform turning of the drill rod and its bit with each successive stroke will, therefore be insured by the conjoint action of the rotative spring seat, and the grooved plate in its coperation with the toothed portion ofv the piston 10.

The drill barrel 2 is provided at diametrically opposite sides at its rear end, with enlargements 65-66, in which boxes 67 are mounted and constitute bearings for the crank shaft 30. The enlargement 65 is made circular and is threaded externally to receive a casing 68 which incloses a gear wheel 69 screwed on the threaded end 70 of the crank shaft 30.

The rear end of the drill barrel is adaptedto support an electric motor 71. The frame of this motor is provided with a rib 72 seated on a shoulder 7 3 on the rear end of the drill barrel. The motor frame is also provided with a shoulder 74 having a groove 75, and this shoulder is disposed alongside a ilange 76. on the gear case. The flange 76 is made with a groove disposed opposite the groove 75 in the shoulder 74, and through these grooves, a bolt or key 78 is passed for locking the motor to the rear end of the drill barrel.

The armature shaft 79 of the motor projects at one end beyond its bearing in the motor frame and is threaded for the reception of a pinion 80. A pinion 81 is mounted on bosses 82-83 projecting respectively from the motor frame and a cover plate 84 secured to the latter, and this pinion 81 serves to transmit motion from the pinion on the armature shaft of the motor to the gear wheel 69 on the crank shaft of the drill.

Numerous slight changes might be made in the details of construction of my invention without departing from the spirit thereof or limiting its scope, and hence I do notwish to limit myself to the precise details herein set forth.

I-Iaving fully described my invention what I claim as new and desire to secure by Letters- Patent, is

1. In a drill, the combination with a drill rod `and a spring for propelling it, of means for compressing the spring and then withdrawing the drill rod and compressed spring, and trip devices for releasing the drill rod from said means.

2.` In a drill, the combination with a drill rod and a spring for propelling it, of means for compressing the spring after the drill rod has moved forwardly and before it begins its return movement, devices cooperating with said means and the drill rod to withdraw the latter after the s ring has been com ressed, and trip devices for releasing the dri rod to the propelling action of said spring.

3. In a drill, the combination with a drill rod and a propelling spring therefor, of means movable in the saine direction as the forward throw of the drill rod to compress said spring, devices for connecting said means with the drill rod after the s ring has been compressed for moving the dri rod and compressed spring rearward during the return movement of said means, and trip devices for releasing the drill rod to the action of the propelling spring.

4. In a drill, the combination with a drill rod and reciprocating means for withdrawing the drill rod, of means for connecting the reci rocating withdrawing means with the dril rod, a propelling spring compressed by the forward movement of ,the withdrawing means, and means for releasing the drill rod from the withdrawing means.

5. In a drill, the combination with a reciprocating drill rod, and a reciprocating draw bar, of a propelling spring compressed by the forward movement of the draw bar, a clutch for connecting the draw bar and drill rod, and means for operating said clutch.

6. In a drill, the combination with a drill rod and a draw bar movable independently of the drill rod in one direction, a pro veiling spring for the drill rod compressed by the draw bar when the latter moves independently of the drill rod, means for causing the drill rod to move rearwardly with the draw bar, and means for releasing the drill rod from the draw bar to permit the spring to propel the drill rod.

7. In a drill, the combination with a drill rod and a reciprocating draw bar, one movable independently of the other in one direction, of a propelling spring disposed axially with respect to the draw bar and drill rod, means for causing the drill rod and draw bar to move together rearwardly, and means for releasing the drill rod from the draw bar to the action of the propelling spring.

S. In a drill, the combination with a drilll ro d, a draw bar movable forwardly independently of the drill rod, and means for reciprocating and simultaneously oscillating the draw bar, of a propelling spring arranged axially with respect to the drill rod and diaw bar, a rotative seat for said spring, means for causing the drill rod to move rearwardly with the draw bar, and means for releasing the drill rod from the draw liar.

9. In a drill, the combination with a drill rod and a draw bar, the former having a tubular portion and one movable independently of the other, of a tubular extension on the draw bar entering the tubular portion of the drill rod, a propelling spring housed within said tubular extension and within the tubular portion of the drill rod, means for causing the draw bar to move independently of the drill rod in one direction, means for causing the drill rod and draw bar to move together in the other direction, and means for releasing the drill rod from. the draw bar.

l0. In a drill, the (annbination with a reN ciprocating drill rod and a reciprocating draw bar, means for moving the draw bar forwardly independently of the drill rod, a propelling spring for the drill rod compressed by the forward movement of the draw bar, a clutch carried by the draw bar, means for causing said clutch to engage the drill rod at the forward end of its throw, and means for operating said clutch at the rear end of the throw of' the draw bar to release the drill rod.

l1. In a drill, the combination with a drill barrel, a drill rod having a hollow piston at its rear end movable in said barrel, a draw bar and means for reciprocating said draw bar, of a wedge block secured. to the draw bar, clutch shoes mounted on said wedge block and entering the hollow piston of the drill rod, a propelling spring compressed by the forward movement of the draw bar, and means for moving the clutch in one direction on the wedge block to cause the clutch shoes to clutch the piston end of the drill rod and means for moving said clutch shoes in the other direction to release the drill rod to the action of the propelling spring.

l2. In a drill, the combination with a drill barrel, a drill rod having a hollow piston movable in the drill barrel, a reciprocating draw bar, and a propelling spring for the drill rod, of a wedge block secured. to the draw bar, a series of clutch shoes on said wedge block and entering the hollow piston of the drill rod, springs tending to move the clutch shoes in a direction to clutch said piston, a trip lever, a yoke connecting said trip lever with the clutch shoes, and means for operating said trip leverI to control the operation of the clutch shoes.

13. ln a drill the combination with a drill barrel, a drill rod having a hollow piston movable therein, a reciprocating draw bar, and a propelling spring for the drill rod, of a wedge blocli secured to the draw bar, a series of clutch shoes on said wedge block and adapted to enter the piston on the drill rod, a hook-shaped arm projecting rearwardly from each clutch shoe, a trip lever pivotally supported by the draw bar, a yolre pivoted at one end to the trip lever and engaged at its other end by the hook-shaped arms oi tie clutch shoes, springs for moving the clutch shoes in one direction to cause them to clutch the piston on the drill rod, and means for op erating the trip lever to move the clutch slices in the other direction to release the drill rod to the action of the propelling spring.

14. ln a drill, the combination with a drill barrel, a drill rod, a draw bar having a cross head movable in the drill barrel and provided with an elongated opening, a shaft having a crank arm movable in the elongated opening in the cross head, and a propelling spring between the drill rod and draw bar, of a clutch carried by the draw bar to engage the drill rod, and a trip lever mounted in the draw bar and connected with the clutch, said trip lever having a part movable in the path of the arm of the crank shaft so as to be operated thereby to operate the clutch and release the drl rod.

15. In a drill, the combination with a drill rod, a draw bar, a propelling spring between the drill rod and draw bar, and a clutch carried by the draw bar and adapted to engage the drill rod, of a crank shaft for reciprocating the draw bar, and a trip lever carried by the draw bar, said trip lever connected with the clutch and having a part movable into the path of the arm of the crank shaft.

16. In a drill, the combination with a drill barrel, and a drill rod, of a propelling spring for forcing the drill rod forv Tardly, means for withdrawing the drill rod and simultaneously turning it, and means tending to prevent the drill rod from turning farther than it is turned by the withdrawing means and means operating automatically to connect said withdrawing means with and disconnect the same from the drill rod.

17. In a drill, the combination with adrill barrel, and a drill rod having elongated peripheral teeth parallel with the axis of the rod, of means for moving said drill rod longitudinally in one direction and simultaneously turning it, and a spring-pressed grooved plate supported by the drill barrel and engaging the toothed portion of the drill rod to offer resistance to the turning of the latter,

18. 1n a drill, the combination with a drill barrel having an elongated opening in its wall, and a drill rod provided with a piston at one end having an annular series of peripheral teeth, of means for moving the drill rod rearwardly and simultaneously turning it, a grooved plate projecting through the opening in the wall of the drill barrel, and a' spring pressing said grooved plates against the toothed portion of the piston on the drill rod.

19. ln a drill, the combination with a drill barrel, a drill rod having a hollow piston movable in the drill barrel, said piston provided with teeth, a draw bar adapted to reciprocate and oseillate a propelling spring disposed between the bar draw and drill rod and arranged axially with respect to both, and means for connecting the draw bar with the drill rod, of a rotative seat for the propelling spring, a grooved plate mounted in the drill barrel, and a spring pressing said plate against the toothed portion of the piston on the drill rod.

20. ln a drill, the combination with a drill barrel, and a drill rod, of a propelling spring for the drill rod, means for compressing said spring and withdrawing the drill rod, means for releasing the drill rod tglthe action of tpe ro ellinO' s rino', and bu g s rinO's for t 1e llrillD redo the forward endP of zjthe drill barrel.

2l. ln a drill, the combination with a drill barrel, a drill rod having a hollow piston movable in the drill barrel, a collar on the drill rod beyond the end of thedrill barrel, and means for reciprocating the drill rod, of bufling springs projecting beyond the forward end of the drill barrel in position to be engaged by the collar on the drill rod, and bufling springs in the forward end of the drill barrel in position to be engaged by the forward end of the piston on the drill rod.

22. 1n a drill, the combination with a drill barrel, a drill rod projecting through the forward end thereof, a collar on the forward portion of said drill rod, and means for reciprocating the drill rod, of a soclieted ring screwed into the end of the drill barrel, a bushing for the drill rod, screwed into said ring, means for locking the bushing, and bulling springs seated in the sockets of the soclreted ring and projecting beyond the same in position to be engaged by the collar on the drill rod when the latter moves rearwardly, and other springs seated in said soelreted ring in position to cushion the forward movement of the drill-rod.

23. 1n a drill, the combination with a drill body or barrel and a drill rod, of a propelling spring arranged in alinement with the axis of the drill rod, a draw bar, means for longitudinally reciprocating and simultaneously rotatably oscillating the draw bar, means for coupling the drll rod with the draw bar 'when the latter moves rearwardly, and means for overcoming torsional strain on the propelling s ring and tending to insure the turning of t e drill rod to the same extent that the draw bar turns during the rearward throw of the latter.

24. In a drill, the combination with a drill rod and propelling means, of a reciprocating clutch device for energizing said propelling' means and then withdrawing the drill rod and energized propelling means, a trip device for releasing the drill rod from the clutch device, and means for rapidly reciprocating said clutch device.

25. In a drill, the combination with a drill rod and a ropelling spring, of a reci recating clutch device for compressing sai( spring and thenwithdrawing the drill rod and compressed spring, a trip device for releasing the drill rod from the clutch device, a crank shaft for reciprocating the clutch device, and means for rapidly rotating said crank shaft.

26. In a drill, the combination with a drill rod, and propelling means therefor, of operating means including a clutch for energizing said propelling means and then withdrawing the drill rod and energized propelling means, means for releasing the drill rod from said operating means, and means lor rapidly reciprocating said operating means and causing the same to quickly follow the released drill rod.

In testimony whereof, I have signed this specification in the presence of two suhscribing Witnesses.

THOMr S EDGAR ADAMS.

lVitnesses It. KAUFFMAN, F. W. SINOAM. 

